CN112526512B - High-power large-caliber broadband millimeter wave air-fed phase control array radar system and imaging method - Google Patents
High-power large-caliber broadband millimeter wave air-fed phase control array radar system and imaging method Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
- G01S13/88—Radar or analogous systems specially adapted for specific applications
- G01S13/89—Radar or analogous systems specially adapted for specific applications for mapping or imaging
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/02—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00
- G01S7/41—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S13/00 using analysis of echo signal for target characterisation; Target signature; Target cross-section
- G01S7/418—Theoretical aspects
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Abstract
The invention discloses a high-power large-caliber broadband millimeter wave air-fed phased array radar system and an imaging method, which are applied to the field of millimeter wave phased array radars and aim at the technical problem that the conventional high-power millimeter wave radar system does not have large-scale electronic beam scanning capability and simultaneous multi-target observation capability; and a broadband space-fed phased array radar system of the step frequency signals is adopted, so that the instantaneous working bandwidth of a radar system is reduced, the antenna beam of the phased array has a large electronic scanning range, and the high distance resolution of a target is obtained through broadband synthesis processing of step frequency echo pulses.
Description
Technical Field
The invention belongs to the field of millimeter wave phased array radars, and particularly relates to a millimeter wave air-feed phased array radar technology for remote target observation and imaging.
Background
With the rapid development of aerospace science and technology and the increasing frequency of manned aerospace activities, the demands for observing the activities and states of spacecrafts, space debris, meteorites and other universe celestial bodies in orbital space from the ground are more and more urgent, and the performance requirements are higher and higher. Compared with an optical system, the radar has the advantages of all weather, all-time and large observation range, and can realize multiple functions such as detection, tracking, precision measurement and radar imaging. In particular, the millimeter wave radar system has high working frequency, can provide large bandwidth, can perform high-precision parameter measurement and high-resolution radar imaging on a space target, and has better performance and application value compared with a microwave radar system.
Typical space observation applications require that a millimeter wave radar can provide at least one hundred kilowatts (kW) to Megawatts (MW) of peak transmitting power, gigahertz (GHz) signal bandwidth, a large-aperture antenna above a meter level, and have large space coverage and simultaneous multi-target observation capabilities, which requirements bring strict limitations and huge challenges to the existing millimeter wave radar technology and system design and implementation thereof. The technical level of millimeter wave solid-state power devices limits the large-aperture solid-state phased array to have huge cost and difficult meeting the requirements on power and action distance, and the conventional high-power millimeter wave radar system is mainly constructed by adopting a high-power centralized electric vacuum transmitter and a mechanical scanning antenna. For example, the MMW Radar (Millimeter Wave Radar, document "j.j.stamp antenna, r.k.lee, and w.h.cantrell.the 4GHz band width meter-Wave Radar [ J ]. Lincoln Laboratory Journal, vol.19, No.2,2012, pp.64-76.") and the HUSIR Radar (Haystack ultra base and Satellite Imaging Radar, document "m.g.czezewski and j.m.usoff.development of the Haystack ultra base and Satellite Imaging [ J ]. Lincoln Laboratory Journal, vol.21, No.1,2014, 28-44.") in the united states use of high power line and klystron + large diameter tube respectively, which achieve low target scanning speed, and only a single target scan; while russian RUZA radar is constructed by a high-power cyclotron tube and a large-caliber millimeter wave phased array (documents "a.a.tolkache v, and b.a.levitan, et al.a megawatt power meter-wave phased-array [ J ]. IEEE Aerospace and Electronic Systems radar, vol.15, No.7,2000, pp.25-31.), the Electronic scanning range of its antenna beam is very narrow (not more than 0.85 °), and large-scale scanning of space (within ± 135 ° of azimuth and within 0 ° to 180 ° of elevation) is still realized by a mechanical scanning manner, so that the RUZA radar has the disadvantages of low radar data rate, few targets that can be observed at the same time, and the like. Therefore, although these radars have a large antenna aperture and a large instantaneous operating bandwidth, they do not have a large-range electronic beam scanning capability and a simultaneous multi-target observation capability, and thus do not perform a space observation task well.
Disclosure of Invention
In order to solve the technical problems, the invention provides a high-power large-caliber broadband millimeter wave air-feed phased array radar system, an antenna array adopts an air-feed mode to feed, the antenna loss is reduced, the aperture efficiency is improved, and the realization difficulty of a large-scale phased array antenna is reduced; the broadband space-fed phased array radar system adopting the step frequency signals is provided, the instantaneous working bandwidth of a radar system is reduced, the antenna beam of the phased array has a large electronic scanning range, and the high distance resolution of a target is obtained through the broadband synthesis processing of step frequency echo pulses.
The technical scheme adopted by the invention is as follows: a high-power large-caliber broadband millimeter wave air-fed phase-controlled array radar system comprises: the system comprises an air-fed phased array antenna, a radar signal generator, a radar transmitter, a radar receiver, a radar signal processor, a radar comprehensive information processor and a wave controller; the air-fed phased array antenna is connected with the input end of the radar receiver, the air-fed phased array antenna is connected with the output end of the radar transmitter, and the air-fed phased array antenna is also connected with the output end of the wave controller; the output end of the radar receiver is connected with the input end of the radar signal processor, and the output end of the radar signal processor is connected with the input end of the radar comprehensive information processor; the output end of the radar comprehensive information processor is respectively connected with the input end of the radar signal generator and the input end of the wave controller; the output of the radar signal generator is respectively connected with the input ends of the radar receiver, the radar transmitter and the radar signal processor;
the air-fed phased array antenna includes: the space feed subsystem and the antenna array system, the space feed subsystem includes at least one horn feed source, the horn feed source is connected with radar transmitter and radar receiver respectively through receiving and dispatching switch, the antenna array system includes: the phase-shifting device comprises a radiating element array, a phase shifter array and a phase configuration network; the radiation element array is used for receiving or transmitting signals, the phase configuration network is used for distributing the phase codes sent by the wave controller to corresponding phase shifters, and the phase shifters are used for adjusting the pointing direction of the radiation element array.
The horn feed source uses a multi-horn mouth antenna, and a sum channel, an azimuth difference channel and a pitch difference channel are formed by combining corresponding horn mouths; specifically, a radio frequency signal output port of the radar transmitter is connected with the sum channel, and a radio frequency signal input port of the radar receiver is respectively connected with the sum channel, the azimuth difference channel and the elevation difference channel.
The antenna array structure of the antenna array system is a transmission array, and comprises: the antenna array comprises a collection array surface and a radiation array surface, wherein the collection array surface is arranged on the same side of the feed source, the radiation array surface is arranged on the back surface of the collection array surface, the collection array surface is used for receiving a transmitting signal sent from the feed source or sending an echo signal received by the antenna back to the feed source, and the radiation array surface is used for transmitting a detection signal or receiving an echo signal.
The phase shifter is positioned between the collection front and the radiation front.
The antenna array surface structure of the antenna array system is a reflective array and comprises an antenna array surface and a reflective surface, and the antenna array surface firstly receives a transmitting signal sent by a feed source during transmitting, and the transmitting signal is radiated towards space by an antenna array after array phase shift and reflection of the reflective surface; during receiving, the antenna array surface firstly receives scattered echo signals from the space, and the scattered echo signals are radiated towards the feed source by the antenna array after being subjected to array phase shift and reflection by the reflecting surface.
A phase shifter is positioned between each radiating element and the reflective surface.
The radar signal generator comprises a reference oscillator, a waveform generation module, a frequency synthesis module and a clock generator, wherein the reference oscillator provides reference frequency signals for the frequency synthesis module and the clock generator, the clock generator provides a reference clock for the waveform generation module, the waveform generation module generates intermediate frequency radar waveforms with specified bandwidth, and the frequency synthesis module generates stepping frequency agility signals and a plurality of dot frequency signals.
And the dot frequency signal is simultaneously sent to the radar transmitter and the radar receiver to be used as a stable local oscillation signal shared by receiving and transmitting.
The waveform generation module includes: the frequency synthesizer is used for generating an intermediate frequency radar waveform with a specified bandwidth, and when the output signal of the digital frequency synthesizer cannot meet the requirement of the broadband, the frequency and the bandwidth of the output signal of the digital frequency synthesizer are increased by using the frequency multiplier.
The invention also provides a target high-resolution imaging method based on the system, which comprises the following steps: a low resolution processing procedure and a high resolution processing procedure; the low resolution processing process specifically comprises the following sub-steps:
A1. performing matched filtering or pulse compression processing on the conventional or modulated pulse signal, wherein the obtained processing result represents the distribution of radar echoes along a low-resolution distance unit;
A2. doppler processing is carried out on each distance unit, and the obtained processing result represents the distribution of the echo on the current distance unit along the Doppler unit;
A3. according to the processing results of the steps A1 and A2, the distribution of the radar echo on the range-Doppler plane is obtained;
A4. for each range-doppler cell, performing target detection;
A5. when a target is judged, the gating and-difference angle measurement module measures the azimuth angle and the pitch angle of the target by using the data of the sum channel, the azimuth difference channel and the pitch difference channel;
A6. for a unit with a target, resolving the distance, speed and angle of the target and forming a trace point of the target;
A7. the radar comprehensive information processor carries out target motion parameter estimation and target tracking according to the trace of the target;
the high resolution processing process comprises the following sub-steps:
B1. performing IFFT processing on the baseband signal along the step frequency direction, mapping radar data to a high-resolution range, and dividing a mapping result into a clutter area and a non-clutter area;
B2. clutter suppression processing, namely setting the distance unit data of the corresponding clutter region to zero;
B3. performing FFT processing on the data processed in the step B2, and remapping the distance domain data back to an original data domain;
B4. according to the target motion parameters obtained in the step A7, motion compensation processing is carried out on the radar data processed in the step B3;
B5. the data subjected to the motion compensation in step B4 is subjected to IFFT processing to generate a high-resolution range image of the object.
The invention has the beneficial effects that: the system of the invention has the following advantages:
1. the proposed radar system uses an air feed phased array system, has no forced feed network, small feeder loss and high antenna efficiency, and can exert the power advantage of a millimeter wave electric vacuum device, thereby realizing a high-power remote millimeter wave phased array radar system;
2. the system structure of the wave form of the air feed array and the step frequency radar has the advantages that the array surface is simple in structure, more millimeter wave radiation units with small sizes can be integrated on the surface of an antenna array, and accordingly the ultra-large-diameter and ultra-large-scale broadband millimeter wave phased array antenna can be constructed;
3. the high-power millimeter wave air-fed phased array radar system can adopt a step frequency radar waveform, can transmit and receive signals with instantaneous narrow bandwidth, avoids the problem of aperture transition existing in the realization of a conventional broadband large-aperture phased array, and enables antenna beams of an air-fed array to carry out large-scale electronic scanning;
4. the proposed space feed array uses a phase method to carry out beam forming and scanning, and the phase shifter realizes the phase shift of signals of each radiation unit without using a time delay device to carry out time delay;
5. the air-fed array system can generate various radar waveforms, realize the emission and the reception of narrowband, broadband and stepping frequency radar signals, can process the radar signals with low resolution and high resolution, and can be used for constructing a multifunctional phased array radar system;
6. the space feed array radar system has the searching and tracking capabilities and the distance high-resolution capabilities on remote targets, and can be used for constructing radar systems such as a space monitoring radar, an imaging radar and a precision measurement radar.
7. The proposed air feed array radar system adopts an electronic beam scanning mode, beam pointing switching is rapid and flexible, and detection tasks on a plurality of space targets can be executed simultaneously.
Drawings
FIG. 1 is a block diagram of a system structure of an air-fed array radar provided by the present invention;
fig. 2 is a structural diagram of a transmission array of an air-fed phased array antenna provided by the invention;
FIG. 3 is a diagram of a reflection array structure of an air-fed phased array antenna provided by the present invention;
FIG. 4 is a block diagram of a radar signal generator provided by the present invention;
FIG. 5 is a block diagram of a radar transmitter provided by the present invention;
FIG. 6 is a process for implementing radar reception, radar signal processing, and radar integrated information processing according to the present invention;
fig. 7 is a typical working scenario of the air-fed phase-controlled radar system provided by the present invention in a space surveillance application.
Detailed Description
In order to facilitate understanding of the technical contents of the present invention by those skilled in the art, the present invention will be further explained with reference to the accompanying drawings.
In order to solve the problem that the electronic scanning range of the wave beam of the existing millimeter wave radar system with large bandwidth, large power and large caliber is too narrow and realize the millimeter wave phased array radar integrating large-scale antenna units, the invention provides a millimeter wave air feed phased array radar system, wherein an antenna array adopts an air feed mode for feeding, thereby reducing the antenna loss, improving the aperture efficiency and reducing the realization difficulty of large-scale phased array antennas; the broadband space-fed phased array radar system adopting the step frequency signals reduces the instantaneous working bandwidth of a radar system, enables antenna beams of a phased array to have a large electronic scanning range, and obtains the high distance resolution of a target through broadband synthesis processing of step frequency echo pulses.
The system composition structure block diagram of the high-power millimeter wave air-fed array radar of the invention is shown in figure 1, which comprises: the large-caliber space-fed phased array antenna comprises a radar signal generator capable of generating various radar waveforms and serving as a spot frequency source and a step frequency agile frequency source, a millimeter wave broadband radar transmitter capable of transmitting high-power conventional pulses and step frequency pulse signals, a millimeter wave broadband radar receiver comprising three receiving channels, a radar signal processor capable of performing low-resolution processing and high-resolution processing, a radar comprehensive information processor used for target tracking, radar resource scheduling and management and instruction control, and a wave controller specially used for calculating phase shifter codes of the phased array antenna.
The large-caliber air-feed phased array antenna comprises a space feed (air feed for short) subsystem and an antenna array system comprising a radiating element array, a phase shifter array and a phase configuration network.
The air feed subsystem can only have one horn feed source, and the horn feed source is respectively connected with the radar transmitter and the radar receiver through the receiving and transmitting switch.
There may also be two horn feeds, one of which is connected to the transmitter and the other of which is connected to the receiver.
The horn feed source uses a multi-horn mouth antenna, and a sum channel, an azimuth difference channel and a pitch difference channel are formed through the combination of corresponding horn mouths. Specifically, the radio frequency signal output port of the radar transmitter is only connected with the sum channel, and the radio frequency signal input port of the radar receiver is respectively connected with the sum channel, the azimuth difference channel and the elevation difference channel.
Preferably, in this embodiment, the horn feed source has five horn mouths, so that the antenna array can form a sum beam Σ and an azimuth difference beam ΔAZAnd a difference in elevation beam ΔEL。
The forming of the sum channel, the azimuth difference channel, and the pitch difference channel by the combination of the corresponding bellmouths is prior art and will not be elaborated in detail in this embodiment.
The structure of the antenna array system can be a transmission array or a reflection array, and the antenna array surface is realized by a radiation unit array.
As shown in fig. 2, the transmissive array contains two antenna fronts: the collecting array surface is arranged on the same side of the feed source and is used for receiving a transmitting signal sent from the feed source or sending an echo signal received by the antenna back to the feed source; a radiation front, which is placed behind the collection front, for transmitting the probe signal or receiving the echo signal.
As shown in fig. 3, the reflective array only contains one antenna array surface, and during transmission, the antenna array surface firstly receives a transmission signal sent by the feed source, and after array phase shift and reflection by the reflective surface, the antenna array radiates towards space; during receiving, the antenna array surface receives scattered echo signals from space, and the scattered echo signals are radiated towards the feed source by the antenna array after being subjected to array phase shift and reflection by the reflecting surface. In order to reduce leakage losses, the illumination range of the feed direction diagram is matched with the shape and size of the array surface.
The phase shifter array is located after the wavefront radiating element. Specifically, a pair of transmissive arrays, located between the collection and radiation fronts, with a phase shifter between each pair of collection and radiation elements; for the reflection array, a phase shifter is arranged between each radiation unit of the antenna array surface and the reflection surface. The phase shifters may be implemented using separate millimeter wave ferrite phase shifters, or using sub-wavelength structure phase shifters (super-surface) integrated with the antenna radiating elements. The phase configuration network is used for distributing the phase code sent by the wave controller to the corresponding phase shifter, the phase code determines the phase adjustment amount of the phase shifter, and when all the phase shifters complete phase configuration and phase adjustment according to the designated code, the wave beam of the antenna array points to the set direction.
The radar signal generator is used for generating an intermediate frequency radar waveform, a stable local oscillator signal required by up/down conversion, and a stepped frequency agility signal, as shown in fig. 4, and mainly includes a reference oscillator, a waveform generation module, a frequency synthesis module, and a clock generator. A highly stable constant temperature crystal oscillator (reference oscillator) provides a reference frequency signal for the frequency synthesizer module and the clock generator. The waveform generation module can generate intermediate frequency radar waveforms with specified bandwidth, such as simple pulses, linear frequency modulation pulses and phase coding pulses, and parameters of the type, the bandwidth, the pulse width, the pulse repetition frequency and the like of the radar waveforms are provided by the radar comprehensive information processing and controlling device. The frequency synthesis module generates a stepped frequency agile signal and a plurality of dot frequency signals. The step frequency agility signal is mixed with the intermediate frequency radar waveform subjected to up-conversion to generate a step frequency pulse signal; the dot frequency signals are simultaneously sent to a radar transmitter and a receiver and used as stable local oscillation signals shared by receiving and transmitting; the clock signal is fed to waveform generation modules, analog-to-digital converters (ADCs), digital-to-analog converters (DACs), and other digital circuit modules as a clock signal or timing reference signal.
The waveform generation module consists of a direct digital frequency synthesizer (DDS) and a frequency multiplier. The DDS generates an intermediate frequency radar signal waveform requiring bandwidth. When the DDS output signal still can not meet the broadband requirement, the frequency and the bandwidth of the DDS output signal are improved by using a frequency multiplier, and an intermediate frequency radar signal with a large broadband is generated.
The high-power radar transmitter is a broadband millimeter wave vacuum tube transmitter with a main vibration amplification structure, and as shown in fig. 5, the high-power radar transmitter mainly comprises a radio frequency exciter, a millimeter wave amplification chain, a high-voltage power supply, a cooling subsystem and a monitoring module.
The radio frequency exciter up-converts input intermediate frequency signals (intermediate frequency broadband signals and intermediate frequency narrowband signals) and obtains radio frequency excitation signals in millimeter wave bands through multi-stage up-conversion. The excitation signal is sent to a millimeter wave amplification chain for power amplification. The local oscillation signal when the radio frequency exciter carries out up-conversion corresponds to the local oscillation signal when the receiver carries out down-conversion.
The millimeter wave amplification chain uses a solid-state amplifier as a driving amplification stage and a high-power vacuum tube amplifier as a final stage (power) amplifier. The vacuum tube amplifier can be realized by adopting a single vacuum tube, and also can be realized by adopting a plurality of vacuum tubes connected in parallel. The high-voltage power supply provides power feed for the vacuum tube amplifier.
The cooling subsystem is used to reduce the temperature of the primary transmitter components of the transmitter. The monitoring module comprises acoustic, optical, electric and gas sensors, can monitor and measure the working state and parameters of the system, performs fault location and isolation, and communicates with the main system. Specifically, the millimeter wave vacuum tube amplifier can be a klystron, a traveling wave tube, a gyrotron and the like.
The transmitted signal of a high-power radar transmitter is recorded as
As shown in fig. 6, the implementation processes of radar reception, radar signal processing, and radar integrated information processing are described in detail below, respectively:
the radar receiver comprises three receiving channels which are sum channels sigmaRAzimuth difference channel deltaAZSum-pitch difference channel ΔELAnd are respectively connected with the sum beam port, the azimuth difference beam port and the elevation difference beam port of the horn feed source. The receiving channel adopts a superheterodyne receiving structure and consists of an analog processing module and a digital processing module. Analog processing module for input radio frequency analog signal
And processing such as filtering, amplifying, down-conversion, automatic gain control and the like is carried out, wherein a stable local oscillation signal used in the down-conversion is shared with that used in the up-conversion of the transmitter. The analog processing module sends the generated intermediate frequency signal to the digital processing module. The digital processing module firstly compares the input signal (intermediate frequency)
) And performing analog-to-digital (A/D) conversion, then performing digital down-conversion (DDC), and finally obtaining digital baseband signals of an in-phase branch (I path) and a quadrature branch (Q path). The sum channel, the azimuth difference channel and the elevation difference channel each generate a pair (I path and Q path) of digital baseband signals
Is taken as an input signal for the radar signal processor.
When step frequency signals are transmitted, a radio frequency exciter in a transmitter firstly carries out multi-stage up-conversion on input intermediate frequency signals, the carrier frequency of the signals is increased to the required high intermediate frequency, then the signals are mixed with step frequency agile signals to generate step frequency radio frequency excitation signals, and then the step frequency radio frequency excitation signals are subjected to power amplification; when receiving the step frequency signal, firstly, the step frequency agile signal which is the same as that in the transmitting is mixed with the received signal, the frequency of the received signal is down-converted to the high and medium frequency which is the same as that of the transmitter, and then the multi-stage down-conversion processing is carried out on the frequency.
The radar signal processor provides two types of signal processing, namely: low resolution processing for regular pulses (chirps, phase codes and simple pulses at non-stepped frequencies) and high resolution processing for stepped frequency pulses. The low-resolution processing treats a potential interested target as a point target, and the basic task of the low-resolution processing is to make target existence judgment and measure parameters such as distance, speed and angular position of the target; high resolution processing treats an object of interest as a distributed object, the basic task of which is to form a High Resolution Range (HRR) image of the detected object or the tracked object. Further, target information and parameters thereof obtained by low resolution processing are processed into traces of points, and the traces of points are sent to a radar comprehensive information processing and controlling device for target motion parameter estimation, target tracking and other processing. In order to get a correct and focused HRR image of the target, high resolution processing requires the use of the measured motion parameters of the target.
Low resolution signal
The processing modules include a pulse compression (or matched filtering) module, a doppler processing module, a target detection module, and a sum-difference angle measurement module. The specific steps of the low resolution processing are as follows:
SLR1: for normal or modulated pulse signals
Performing matched filtering or pulse compression to obtain signal
The processing result represents the distribution of radar echoes along the low-resolution range bins;
SLR2: doppler processing is carried out on each distance unit to obtain signals
The processing result represents the distribution of the echo on the current range unit along the Doppler unit;
SLR3: forming the distribution of the radar echo on a range-Doppler plane according to the processing results of the previous two steps;
SLR4: for each range-Doppler cell (Sigma) of the sum channel(2)) Detecting the target and judging whether the target exists or not;
SLR5: when the target is judged to exist, the gating sum-difference angle measurement module utilizes the data of the sum channel, the azimuth difference channel and the pitch difference channel
Measuring the azimuth angle and the pitch angle of a target;
SLR6: and for the unit with the target, resolving the distance, the speed and the angle of the target, forming a point trace of the target, and providing the point trace to the radar comprehensive information processing and control device.
High resolution signal
The processing module comprises a distance domain mapping (IFFT) module, a clutter suppression module, a data domain mapping (FFT) module and a target motion compensation module. The specific steps of the high-resolution processing are as follows:
SHR1: in the step frequency direction, the sum channel baseband signal
Performing IFFT processing, mapping radar data to a high-resolution range, wherein the mapping result can be divided into a clutter area and a non-clutter area;
SHR2: clutter suppression processing of range bin data Z corresponding to clutter regionRSet to zero to obtain
SHR3: for data
FFT processing is carried out, the distance domain data is remapped to the original data domain to obtain
SHR4: performing motion compensation processing on the radar data according to the obtained target motion parameters;
SHR5: the motion compensated data is subjected to IFFT processing to generate an HRR image of the target.
The radar comprehensive information processor mainly comprises a target tracking module, a radar resource scheduling and managing module and an instruction control and configuration module. The target tracking module carries out data processing on the traces sent by the radar signal processor, and the basic processing steps comprise: target position and motion parameter estimation, track initiation, data aggregation, tracking filtering, track termination, target position prediction and the like. The radar resource scheduling and managing module is responsible for arranging radar task sequences, managing tasks such as target searching, capturing, tracking and measuring, distributing and managing energy and time-frequency resources of the radar system, and modifying working parameters of each subsystem through the instruction control and configuration module. Specifically, the radar resource scheduling and managing device mainly works as follows:
1) maintaining and managing a target database of a current radar observation space, arranging and managing a radar task queue, executing tasks such as target searching, capturing, tracking, measuring and re-capturing, and analyzing the motion rule of a tracked target;
2) according to the radar task and the observation performance requirement, determining radar transmission waveform parameters, and sending the parameters to a radar signal generator to generate corresponding transmission radar waveforms;
3) determining the antenna beam direction of the next radar transmission according to the guiding information received by the system or the predicted position of the tracked target, and sending the antenna beam direction to the wave controller to calculate the phase code of each phase shifter of the air feed array;
4) according to 2) and 3), generating control and configuration command words for modifying the working states of the radar transmitter, the radar receiver and the radar signal processor, and adjusting the working states of the subsystems through a command control and configuration module;
5) collecting the execution result of the current radar task, updating a target database and a radar task queue, and switching to execute the next radar task;
6) receiving the state and monitoring information returned by each subsystem or module, and generating and submitting the report information to the system.
And the wave controller calculates the phase shift quantity of each phase shifter in the array antenna according to the antenna beam direction transmitted by the radar next time from the radar comprehensive information processor, converts the phase shift quantity into phase codes and then transmits the phase codes to the array antenna for phase matching.
The present invention is further described below with reference to specific data:
a typical working scenario of the millimeter wave air-fed phase-controlled radar system proposed by the present invention in a space surveillance application is shown in fig. 7. The radar can execute observation tasks aiming at various types of space targets. The radar can transmit high-power millimeter wave signals, the antenna aperture is large, the gain is high, and the maximum action distance can reach kilokilometer magnitude.
The radar antenna uses an air feed phase control array system, a forced feed network is not needed, the feed loss is small, the aperture efficiency is high, the array implementation structure is simple, a large number of small-size radiating units can be integrated on the array surface, and it is ensured that the beam grating lobe does not appear in an observation airspace in which the radar is interested. The beam scanning of the air-feed array adopts an electric scanning mode, and the beam pointing control is flexible and quick, so that the radar can execute simultaneous multi-target observation tasks in a time division mode.
In particular, the proposed radar system is capable of performing the tasks of target searching, capturing, tracking, measuring, and high resolution range imaging. The radar waveform is determined by its corresponding radar task. The radar is capable of generating simple pulses without modulation, as well as chirp and phase-coded pulses. Specifically, parameters of the radar waveform are determined according to factors such as a radar task, the size of the cross section of the target radar, the size of the target and the motion characteristics of the target.
The carrier frequency of the pulse train signal transmitted by the radar can be a fixed frequency, or can be a stepped frequency pulse signal which is increased along the pulse transmission period. Further, whether fixed-frequency or stepped-frequency signals are transmitted is determined by the scanning angle (the included angle between the beam direction and the antenna normal direction) requirement of the radar task on the empty feed array beam and the signal bandwidth requirement. Specifically, radar tasks can be divided into the following three categories:
1) when a large-range target searching and tracking task is executed, the air-fed phased array is required to carry out large-angle beam scanning, the radar signal generator generates a narrow-band or medium-bandwidth pulse waveform, the radar system transmits and receives a pulse train signal with fixed central frequency, and the radar signal processor carries out low-resolution signal processing;
2) when a target approaches to the normal area of the empty feed array antenna and a target fine observation and high-precision parameter measurement task is executed, the required scanning angle of an empty feed array beam is small, and a radar system can use a broadband pulse train signal of a fixed carrier frequency as a task waveform;
3) when a large-range high-precision target tracking and measuring task and a target HRR imaging task are executed, the air feeder array is required to carry out wide-angle beam scanning, the radar signal generator generates narrow-band pulse waveforms, the radar transmits and receives step frequency pulse string signals, the radar signal processor carries out high-resolution signal processing, signals with large bandwidth can be synthesized, and an HRR image of the target is obtained.
Suppose a radar system is to perform an observation task on a target in a space, the distance between the target and the radar is 800km, and the radar cross-sectional area (RCS) is about 1m2。
Operating frequency f of the radar system0When the radar searches the space target, a narrow-band chirp burst signal is transmitted, the signal bandwidth is 10MHz, the pulse length is 100 mus, the pulse repetition frequency is 150Hz, the peak transmission power of the radar transmitter is 100kW, and the noise coefficient of the receiver is 2 dB. The array surface of the air feed array is square, and the aperture size is 3m multiplied by 3mThe normal direction of the array surface points to the zenith, the monitoring area is a spherical crown area right above the radar system, the maximum scanning angle is 60 degrees, the radiation units are arranged according to a uniform square grid, the maximum unit interval is 4mm, the antenna array surface totally contains 52.25 ten thousand units, the width of the main lobe of an antenna beam is about 0.13 degrees, and the maximum gain of the antenna is 63dB (the normal direction of the antenna). According to the radar equation, the signal-to-noise ratio of a single pulse which can be obtained by the radar can be calculated to be about 7dB, and if coherent accumulation of 16 pulses is carried out on echo signals, and the required coherent accumulation time is about 107ms, the signal-to-noise ratio after coherent accumulation is 19 dB. Obviously, the radar system can detect the target with the distance of 800km
When the radar task is to obtain an HRR image of a space target, the radar transmits a step frequency pulse train signal, the pulse waveform is a simple pulse, the pulse length is 0.1 mu s, the frequency step amount is 10MHz, the number of step frequency pulses is 512, the pulse repetition frequency is 100kHz, the time length of the step frequency pulse train is 5.1ms, the coherent accumulation is carried out for 20 times, and the accumulation time length is 102 ms. After the bandwidth synthesis processing, the total synthesized bandwidth is 5.12GHz, the distance resolution is about 3cm, the length of a non-fuzzy distance window is 15m, and the actual equivalent pulse repetition frequency is 195 Hz. Thus, the present invention can obtain a High Resolution Range (HRR) image of the target by transmitting the stepped frequency signal.
It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (9)
1. A method of high resolution imaging of an object, comprising: a low resolution processing procedure and a high resolution processing procedure; the low resolution processing process specifically comprises the following sub-steps:
A1. performing matched filtering or pulse compression processing on the conventional or modulated pulse signal, wherein the obtained processing result represents the distribution of radar echoes along a low-resolution distance unit;
A2. doppler processing is carried out on each distance unit, and the obtained processing result represents the distribution of the echo on the current distance unit along the Doppler unit;
A3. according to the processing results of the steps A1 and A2, the distribution of the radar echo on a range-Doppler plane is obtained;
A4. for each range-doppler cell, performing target detection;
A5. when a target is judged, the gating and-difference angle measurement module measures the azimuth angle and the pitch angle of the target by using the data of the sum channel, the azimuth difference channel and the pitch difference channel;
A6. for the unit with the target, resolving the distance, speed and angle of the target, and forming a trace point of the target;
A7. the radar comprehensive information processor carries out target motion parameter estimation and target tracking according to the trace points of the target;
the high resolution processing process comprises the following sub-steps:
B1. performing IFFT processing on the echo signal along a step frequency direction, mapping radar data to a high-resolution range, and dividing a mapping result into a clutter area and a non-clutter area;
B2. clutter suppression processing, namely setting the distance unit data of the corresponding clutter region to zero;
B3. performing FFT processing on the data processed in the step B2, and remapping the distance domain data back to an original data domain;
B4. according to the target motion parameters obtained in the step A7, motion compensation processing is carried out on the radar data processed in the step B3;
B5. the data subjected to the motion compensation in step B4 is subjected to IFFT processing to generate a high-resolution range image of the object.
2. The method for high-resolution imaging of the target according to claim 1, wherein the method is based on a high-power large-caliber broadband millimeter wave air-fed phased array radar system, and comprises the following steps: the system comprises an air-fed phased array antenna, a radar signal generator, a radar transmitter, a radar receiver, a radar signal processor, a radar comprehensive information processor and a wave controller; the air-fed phased array antenna is connected with the input end of the radar receiver, the air-fed phased array antenna is connected with the output end of the radar transmitter, and the air-fed phased array antenna is also connected with the output end of the wave controller; the output end of the radar receiver is connected with the input end of the radar signal processor, and the output end of the radar signal processor is connected with the input end of the radar comprehensive information processor; the output end of the radar comprehensive information processor is respectively connected with the input end of the radar signal generator and the input end of the wave controller; the output of the radar signal generator is respectively connected with the input ends of the radar receiver, the radar transmitter and the radar signal processor;
the air-fed phased array antenna includes: space feed subsystem and antenna array system, the space is presented the subsystem and is included a loudspeaker feed source, and the loudspeaker feed source is connected with radar transmitter and radar receiver respectively through receiving and dispatching switch, the antenna array system includes: the phase-shifting device comprises a radiating element array, a phase shifter array and a phase configuration network; the radiation element array is used for receiving or transmitting signals, the phase configuration network is used for distributing the phase codes sent by the wave controller to corresponding phase shifters, and the phase shifters are used for adjusting the pointing direction of the radiation element array.
3. The method of claim 2, wherein the space-feed system comprises two horn feeds, one horn feed being connected to the transmitter and the other horn feed being connected to the receiver.
4. The method according to claim 2 or 3, wherein the horn feed source uses a multi-horn antenna, and forms a sum channel, an azimuth difference channel and a pitch difference channel by a combination of corresponding horns; specifically, a radio frequency signal output port of the radar transmitter is connected with the sum channel, and a radio frequency signal input port of the radar receiver is respectively connected with the sum channel, the azimuth difference channel and the elevation difference channel.
5. The method as claimed in claim 4, wherein the antenna array structure of the antenna array system is a transmissive array, comprising: the receiving device comprises a collecting array surface arranged on the same side of a feed source and a radiation array surface arranged on the back of the collecting array surface, wherein the collecting array surface is used for receiving a transmitting signal sent from the feed source or sending an echo signal received by an antenna back to the feed source, and the radiation array surface is used for transmitting a detection signal or receiving an echo signal.
6. The method of claim 4, wherein the antenna array structure of the antenna array system is a reflective array, and comprises an antenna array and a reflective surface, wherein the antenna array receives a transmission signal from the feed source first during transmission, and the antenna array radiates in space after array phase shift and reflection by the reflective surface; during receiving, the antenna array surface firstly receives scattered echo signals from the space, and the scattered echo signals are radiated towards the feed source by the antenna array after being subjected to array phase shift and reflection by the reflecting surface.
7. The method of claim 5, wherein the radar signal generator comprises a reference oscillator, a waveform generation module, a frequency synthesizer module and a clock generator, the reference oscillator provides a reference frequency signal for the frequency synthesizer module and the clock generator, the clock generator provides a reference clock for the waveform generation module, the waveform generation module generates the intermediate frequency radar waveform with a specified bandwidth, and the frequency synthesizer module generates the step frequency agile signal and the plurality of dot frequency signals.
8. The method according to claim 7, wherein the dot frequency signal is simultaneously sent to the radar transmitter and the radar receiver as a stable local oscillator signal for transceiving.
9. The method of claim 8, wherein the waveform generation module comprises: the frequency synthesizer is used for generating an intermediate frequency radar waveform with a specified bandwidth, and when the output signal of the digital frequency synthesizer cannot meet the requirement of the broadband, the frequency and the bandwidth of the output signal of the digital frequency synthesizer are increased by using the frequency multiplier.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3147687A1 (en) * | 2015-09-28 | 2017-03-29 | Institute of Electronics, Chinese Academy of Sciences | Method and device for real-time processing of elevation digital beam-forming |
| CN110609276A (en) * | 2019-09-12 | 2019-12-24 | 北京理工大学 | Broadband monopulse tracking radar system with parabolic antenna |
| CN110967692A (en) * | 2019-12-24 | 2020-04-07 | 上海无线电设备研究所 | Imaging method |
| CN111913180A (en) * | 2020-07-06 | 2020-11-10 | 南京航空航天大学 | Satellite-borne SAR high-resolution wide-range imaging method based on two-channel transceiving split |
Family Cites Families (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4983982A (en) * | 1989-10-16 | 1991-01-08 | Raytheon Company | Space fed phased array antenna with dual phase shifter |
| US5389939A (en) * | 1993-03-31 | 1995-02-14 | Hughes Aircraft Company | Ultra wideband phased array antenna |
| US6184838B1 (en) * | 1998-11-20 | 2001-02-06 | Hughes Electronics Corporation | Antenna configuration for low and medium earth orbit satellites |
| CN1158537C (en) * | 2002-08-06 | 2004-07-21 | 东南大学 | Heterodyne millimetric wave space electricity-feeding transmission method and its focal array imaging structure |
| CN111183747B (en) * | 2013-11-07 | 2016-09-07 | 中国兵器工业第二0六研究所 | Millimeter wave air-fed phased array antenna |
| CN103616671B (en) * | 2013-11-19 | 2016-02-24 | 北京航空航天大学 | A kind of phased-array radar Digital Simulation System and emulation mode thereof |
| CN206301040U (en) * | 2016-12-29 | 2017-07-04 | 南京长峰航天电子科技有限公司 | A kind of radio system that can meet microwave system ultra-wide frequency agility |
| CN108539418B (en) * | 2018-05-25 | 2023-05-16 | 西安欣创电子技术有限公司 | Phased array radar antenna control system and method |
| CN110244272B (en) * | 2019-06-14 | 2022-12-23 | 西安电子科技大学 | Direction-of-arrival estimation method based on rank-denoising model |
| CN110690575A (en) * | 2019-10-14 | 2020-01-14 | 南京恩瑞特实业有限公司 | Novel radar simulation radiation source phased array antenna horn feed source |
| CN110854547B (en) * | 2019-12-05 | 2021-09-24 | 电子科技大学 | Array feed type large-range beam scanning reflector antenna |
| CN111796276A (en) * | 2020-05-25 | 2020-10-20 | 北京理工大学 | Double-active composite imaging method based on millimeter waves |
-
2020
- 2020-11-23 CN CN202011318612.7A patent/CN112526512B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3147687A1 (en) * | 2015-09-28 | 2017-03-29 | Institute of Electronics, Chinese Academy of Sciences | Method and device for real-time processing of elevation digital beam-forming |
| CN110609276A (en) * | 2019-09-12 | 2019-12-24 | 北京理工大学 | Broadband monopulse tracking radar system with parabolic antenna |
| CN110967692A (en) * | 2019-12-24 | 2020-04-07 | 上海无线电设备研究所 | Imaging method |
| CN111913180A (en) * | 2020-07-06 | 2020-11-10 | 南京航空航天大学 | Satellite-borne SAR high-resolution wide-range imaging method based on two-channel transceiving split |
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